/Engine/Source/Runtime/Slate/Public/Framework/Notifications/NotificationManager.h
Called back from the SlateApplication when a window is activated/resized We need to keep notifications topmost in the z-order so we manage it here directly as there isn't a cross-platform OS-level way of making a 'topmost child'.
void ForceNotificationsInFront ( const [TSharedRef](API\Runtime\Core\Templates\TSharedRef)< [SWindow](API\Runtime\SlateCore\Widgets\SWindow) > InWindow )